A walk behind lawn mower comprises a chassis onto which wheels, a handle and a rotating cutting blade is arranged. If the lawn mower is motor driven, it comprises an engine which is arranged to rotate the cutting blade and/or drive one or more of the lawn mower wheels.
It is desirable to enable height adjustment of the lawn mower chassis, for example depending on the length of the grass to be cut, or the topography of the lawn.
Height adjustment is often provided for by axle arrangements comprising a lot of parts. A common solution is a separate machined wheel axle which is welded or stamped to link arms which are pivotally arranged on the chassis, such that by locking the link arms in different pivot positions relative to the chassis, the distance between the ground and the wheel axle may be varied according to a current situation.
A problem is that the link arms need to be made of thick steel plate because they take the load from the wheel axles.
Moreover, tubes are welded to the link arms for providing the pivot fastening interface to the chassis and holders for ball bearings.
A separate transversal rod is normally used to connect the left and right wheels if they are to be height adjustable synchronously, by adjusting only one of them.
The transversal rod too is often welded to the link arms.
A problem is hence that traditional height adjustment arrangements are rather complicated, for example since there are several critical factors in a welding process that affects the results, such height adjustment arrangements are time consuming and costly to produce.